He used to be one of the generational holdouts, a cigar-smoking, beer-swilling bon-vivant who loved his late nights almost as much as he hated his early mornings.

But for Darren Clarke, it became a simple proposition. If he couldn't beat his fitness-minded fellow professionals, he pretty much had to join them.

"Two years ago, I don't know whether I could have done this," said Clarke yesterday after shooting a sizzling 65 to grab the first-round lead over the physically demanding Whistling Straits layout in Kohler, Wisconsin.

"Probably not, in fact. It's a hard walking course."

Clarke has lost 40 pounds since he gave in to the fitness craze 17 months ago. Now, when his opponents pass him on the way to the gym at the crack of dawn, he's not coming in from a night of carousing. He has been fighting the flab with his trainers.

"I'll tell you if (the self-denial) has paid off at the end of this week," he said.

Clarke takes a one-shot lead over Justin Leonard and Ernie Els into today's second round of the PGA Championship.

Vijay Singh, Scott Verplank, Englishman Luke Donald and Briny Baird are another stroke back after a surprisingly easy scoring day as Whistling Straits debuted as a major championship golf course.

Sixty players shot even par or better yesterday on a course that was expected to yield a fraction of that many good scores.

"I think they were pretty nice to us with the tee markers and some of the pins," said American Jay Haas, tied in a nine-man logjam at four-under par. "I guess the PGA is a lot like us: they don't know quite what to expect.

"Early this week I agreed with most of the others that this was the hardest golf course I'd ever seen. Obviously, that changed with the wind direction and the course setup (yesterday)."

Included with Haas in that group at four-under 68 is Canadian Stephen Ames.

Mike Weir, the other Canadian in the field, stumbled out of the gate and could manage only a 73, one-over par.

Weir wasn't the only big name who couldn't take advantage of yesterday's soft conditions.

Tiger Woods struggled to a three-over-par 75.

Davis Love sits at seven-over 79 and John Daly saw his Ryder Cup hopes all but dashed when he shot 81.

EARLY TEE TIME

Last year's champion, Shaun Micheel, shot 77, while Rich Beem, who won this title two years ago, shot 78.

In addition to his new physique, Clarke credited several days of putting instruction from guru Stan Utley for his hot round.

Clarke also had an early tee time when the conditions on the course were most favourable.

"We got fortunate with the conditions this morning," said Clarke. "The greens were holding so we were able to fire right at the flags."

Clarke's threesome included Leonard and K.J. Choi, who shot 68. Between them, that group was 17-under-par yesterday.